Cold-cathode counter tube circuit arrangement



Feb. 1111958 G. o. CROWTHER 2,823,336

COLD-CATHODE COUNTER TUBE CIRCUIT ARRANGEMENT Filed March 21, 1956 FIG.I

-FIG.2

INVENTOR GERALD OFFLE Y CROWTHER rhini- United States Patent COLD-CATHODE COUNTER TUBE CIRCUIT ARRANGEMENT Gerald Otliey Crowther, New Malden, England, assignor,

by mesne assignments, to North American Philips Company, Inc, New York, N. Y., a corporation of Delaware Application March 21, 1956, Serial No. 573,008

Claims priority, application Great Britain March 31, 1955 8 Claims. (Cl. 31584.6)

The present invention relates to circuit arrangements for cold-cathode counter tubes. More particularly, the invention relates to circuit arrangements for Dekatron type tubes.

It is known to use Dekatron counting tubes for the purpose of recording a count. If it is desired to record a count of more than ten, it is necessary to utilize two or more such tubes. Such tubes are thus connected in cascade, so that two will count up to 99 and three will count up to 999 and so on, a pulse being passed on to the next succeeding tube for each rotation of glow discharge of the next preceding tube. In known circuit arrangements, it is not possible to take this output pulse from one tube and feed it directly (that is, without further amplification) to the next tube, since the output is insufficient for this purpose/ Thus, in known circuits, either a cold-cathode tube or high-vacuum tube amplifier is provided between two cascade counters.

In the known Dekatron tubes the transfer of discharge from one cathode to the next is effected by means of two guides, the guide next-to .the cathode in the direction of rotation of the glow discharge is termined the auxiliary cathode and the next one, again in the direction of rotation of the glow discharge, is termed the control electrode. In known circuits, the input pulse is applied to both the auxiliary cathode and the control electrode, the arrangement being such that the potential of the aux iliary cathode reaches its breakdown point before the control electrode reaches its breakdown potential. This may be arranged by delaying the pulse to the control electrode or by making the amplitude of said pulse less than that applied to the auxiliary cathode.

The object of the invention is to provide a circuit a1- rangement in which there is no need to amplify the output signal from one counter tube before applying it to the next tube. A further object is to provide a circuit arrangement which requires only one pulse to be applied to the tube to effect a transfer in the glow discharge from one rest position to the next.

The present invention utilizes at least two glow dis charge tubes connected in cascade, each having a plurality of electrode groups. and a common anode and each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, and in which the discharge from one group to the next may be transferred by means of a negative pulse at the control electrodes connected together. In accordance with the present invention, a negative pulse is passed on from the common anode without further amplification to the control electrodes of the next succeeding counting tube only during the transfer of the discharge from the last group of electrodes to the first, said pulse in said next succeeding tube causing the discharge to pass on to a next group of electrodes. The discharge current in each rest position, at least in the next succeeding tube, is preferably shared between the relative cathode and the corresponding auxiliary cathode, so that the current to the latter is considerably greater than that to the former.

2,823,335 Patented l 'eh. H M19578 The main cathode of the last group of each counting tube, independently of the other main cathodes connected together, is connected to ground via a resistor shunted by a capacitor. Said main cathode is also connected via a second resistor to the anode of a rectifier and to a second capacitor, the cathode of the rectifier being connected via a third capacitor to the common anode of he tube and via a resistor to the auxiliary cathodes. The second capacitor is connected to the control electrodes of the next succeeding counting tube.

In order that the invention may be readily carried into effect, it will now be described, by way of example, with reference to the accompanying drawing, in which:

Fig. 1 is a schematic diagram of a one stage embodiment of a Dekatron tube counting arrangement in accordance with the present invention; and

Fig. 2 is a schematic diagram of a two stage embodiment of a Dekatron tube counting arrangement in accordance with the present invention.

In Fig. 1, the reference numeral 1 designates the anode of a Dekatron counting tube, which anode is connected through a resistor 2 to a source of positive potential with respect to ground. The portion of the tube shown comprises an eighth main cathode 8 an auxiliary cathode and a control electrode fi and 8 respectively, a ninth main cathode 9 and an auxiliary cathode 9 The main cathode 8 is connected to ground via a resistor 11 shunted by acapacitor 12. The zero, second, fourth and sixth main cathodes (not shown) are connected internally of the tube to the main cathode 8 and the first, third, fifth and seventh main cathodes (not shown) are similarly connected to ground through a resistor and a capacitor (not shown). The main cathode 9 is provided, independently of the others, with a resistor 13 and a capacitor 14, but has no other main cathodes connected to it. All of the auxiliary cathodes, which are connected together, are connected to source of constant voltage which is positive with respect to ground, for example +40 volts, but which is less than the voltage applied to the common anode, and all ofthe control electrodes, which are also connected together, are connected to said constant positive voltage source through a fairly high resistor 3. Between the anode 1 and the main cathode 9;; there are connected in series a capacitor 15, a rectifier 16 and a resistor 17, the junction between capacitor 15 and the cathode of rectifier 16 being connected through a resistor 18 to the +40 volt source, that is to the auxiliary cathodes. The junction between the anode of rectifier 16 and resistor 17 is connected through a capacitor 19 to an output terminal 20, which is for connection to the control electrodes of the next succeeding tube.

It may be assumed that the glow discharge is at the eighth position and that the discharge spreads over main cathode 8 and auxiliary cathode 8 Resistor 11 has a selected resistance value such that the current to main cathode 8 is many (for example, 30) times smaller than that to auxiliary cathode 8 and as a result the potential of main cathode fi adjusts itself so that it is the same as that of the auxiliary cathode 8 that is, +40 volts.

When a negative pulse is applied to the control electrodes via the terminal 5 and capacitor 4, part of the glow discharge passes on to the control electrode 8 Which in turn passes on the discharge to the main cathode 9 since the gap between the main cathode and the anode 1 has the full anode to ground voltage across it; the main cathode 9 initially being at ground potential. The glow discharge initially transfers wholly to the main cathode 9 so that its voltage rises to that of the auxiliary cathode 9 whereupon the glow discharge spreads over these two electrodes, the current to the main cathode 9 due to the resistor 13 again being very much smaller than that to the auxiliary cathode 9 The glow discharge rests here until the receipt of the next input pulse. At the instant of initiation of the discharge to the main cathode 9 when this cathode is still at ground potential, the anode potential falls rapidly to the burning voltage between these two electrodes and thereafter rises with the rising potential of the main cathode 9 since capacitor 14 is charged. Thus, a negative pulse is produced at the anode, which pulse is applied to the cathode of rectifier 16, but since the cathode of said rectifier has a potential of +40 volts and the anode of the rectifier initially is at ground potential, the said rectifier remains blocked and no negative pulse appears at terminal 29. On receipt of the next input pulse, the glow discharge transfers to the tenth or zero position in the manner described in connection with the transfer from the eighth to the ninth position, and again a negative pulse is produced at the anode 1; in this case due to the charge of capacitor 12. However, this time the potentials of the anode and the cathode of rectifier 16 are substantially equal, due to the voltage drop produced across resistor 13 and capacitor 14, so that the negative anode pulse is passed through the rectifier 16 and capacitor H to the terminal 20. If the control electrodes of a succeeding counting tube are connected to the terminal 20, the negative pulse produced at terminal 249 will cause the discharge in said succeeding tube to step one position. Since a negative pulse appears at terminal 24} only when the glow discharge is transferred from the ninth to the tenth or zero position, the next succeeding tube counts the number of complete rotations of the discharge in the next preceding tube each rotation correspond ing to the receipt of ten input pulses.

Fig. 2 shows a circuit arrangement, in which two counting tubes are connected in cascade, the same reference numerals being used for similar parts of the circuits of Figs. 1 and 2. If desired, similar tubes may be connected in cascade to achieve the required count.

The speed of these counters is to some extent restricted by the time constants involved, especially that associ: ated with capacitor 19, but the speed may beincreased by the addition of a rectifier connected across resistor 21 with its anode connected to the auxiliary cathodes, so that capacitor 19 nyaym'ore quickly discharge.

An improvgentin a counting device as a whole is obtained by bending the upper ends of the main cathode wlres and those of the control electrodes into an -shape, the bent portion of each main cathode pointing towards the control electrode of the preceding group of electrodes, as viewed in the direction of rotation of the glow discharge. Such bending will, of course, necessitate a change in spacing of electrode wires to accommodate the bent portions.

While the invention has been described by means of specific examples and in specific embodiments, I do not wish to be limited thereto, for obvious modifications will occur to those skilled in the art without departing from the spirit and scope of the invention.

What is claimed is:

1. A device for counting pulses by means of at least two glow discharge counting tubes connected in cascade, each tube comprising a number of electrode groups and a common anode and each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, the discharge being transferred from one group to the next by means of a negative pulse at the control electrodes connected together, characterized in that only during the transfer of the discharge from the last group of electrodes to the first a negative pulse is transferred from the common anode, without further amplification, to the control electrodes of the next counting tube and causes the discharge in this tube to transfer to a next group of electrodes.

' 2. A device as claimed in claim 1, characterized in that at least in the next counting tubes the discharge in the rest position rests substantially on the auxiliary cathode of the relative group of electrodes and for a smaller part on the main cathode of the last group of electrodes of the tube, independently of the other main cathodes connected together, being connected to earth via a resistor shunted by a capacitor and connected via a second resistor to the anode of a rectifier and a second capacitor, the cathode of the rectifier being connected via a third capacitor to the common anode of the counting tube and via a resistor to the auxiliary cathodes, whilst the second capacitor is connected to the control electrodes of the next counting tube.

3. A device as claimed in claim 1, characterized in that the main cathodes, except those of the last group, are interconnected and connected to earth via a common resistor shunted by a capacitor, all of the auxiliary cathodes being directly connected to a voltage source having a voltage which is positive with respect to earth, but lower than the positive voltage, to which the common anode is applied via a resistor.

4. A circuit arrangement for counting pulses by means of at least two glow discharge counting tubes connected in cascade, each of said tubes being of the type having a number of electrode groups and a common anode, each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, the control electrodes of said groups being connected together and the discharge in said tube being transferred from one of said groups to the next of said groups by means of a negative pulse applied to said control electrodes, comprising means for transferring a negative pulse from said common anode of one of said counting tubes substantially directly to said control electrodes of the next succeeding counting tube upon the transfer of the discharge of said one tube from the last group pfilee trodes to the first group of electrodesihereby to transfer the discharge of grid/next "succeeding tube from one gpp ofreleetrodes to the next group of electrodes.

circuit arrangement for counting pulses by means of at least two glow discharge counting tubes connected in cascade, each of said tubes being of the type having a number of electrode groups and a common anode, each group of electrodes comprising a main cathode, anauxiliary cathode and a control electrode, the control electrodes of said groups being connected together, and the discharge in said tube being transferred from one of said groups to the next of said groups by means of a negative pulse applied to said control electrodes, comprising means for transferring a negative pulse from said common anode of one of said counting tubes substantially directly to said control electrodes of the next succeeding counting tube upon the transfer of the discharge of said one tube from the last group of electrodes to the first group of electrodes thereby to transfer the discharge of said next succeeding tube from one group of electrodes to the next group of electrodes, means for feeding a portion of the discharge current of each of said tubes to the auxiliary cathode of a group of electrodes and a relatively smaller portion to the main cathode of said group of electrodes, the main cathode of the last of said groups being independent of the other main cathodes, a first resistor, a first capacitor connected in shunt across said first resistor, means for connecting the main cathode of-said last group of electrodes of one of said tubes to a point at ground potential through said first resistor, a rectifier having an anode and a cathode, a second resistor connected between the main cathode of said last group of electrodes and the anode of said rectifier, a second capacitor connected between the cathode of said rectifier and said common anode, a third capacitor connected between the junction point of said second resistor and said rectifier and the control electrodes of said next succeeding tube, and resistive means connecting the junction point of said rectifier and said second capacitor to the auxiliary cathodes of said one tube.

6. A circuit arrangement for counting pulses by means of at least two glow discharge counting tubes connected in cascade, each of said tubes being of the type having a number of electrode groups and a common anode, each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, the control electrodes of said groups being connected together, the auxiliary cathodes of said groups being connected together, and the discharge in said tube being transferred from one of said groups to the next of said groups by means of a negative pulse applied to said control electrodes, comprising means for transferring a negative pulse from said common anode of one of said counting tubes substantially directly to said control electrodes of the next succeeding counting tube upon the transfer of the discharge of said one tube from the last group of electrodes to the first group of electrodes thereby to transfer the discharge of said next succeeding tube from one group of electrodes to the next group of electrodes, means for connecting selected ones of said main cathodes together, a resistor, a capacitor connected in shunt across said resistor, means for connecting the others of said main cathodes together and to a point at ground potential through said resistor, the main cathode of the last of said groups being independent of the other main cathodes, means for biasing said common anode at a positive potential with respect to said point at ground potential, a source of potential positive with respect to said point at ground potential and of relatively smaller magnitude than that of said biasing means, and means for connecting said source of potential to said auxiliary cathodes.

7. A circuit arrangement for counting pulses including a glow discharge counting tube of the type having a number of electrode groups and a common anode, each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, the control electrodes of said groups being connected together, the auxiliary cathodes of said groups being connected together, and the discharge in said tube being transferred from one of said groups to the next of said groups by means of a negative pulse applied to said control electrodes, comprising means for feeding a portion of the discharge current to the auxiliary cathode of a group of electrodes and a relatively smaller portion to the main cathode of said group of electrodes, the main cathode of the last of said groups being independent of the other main cathodes, a first resistor, a first capacitor connected in shunt across said first resistor, means for connecting the main cathode of said last group of electrodes to a point at ground potential through said first resistor, a rectifier having an anode and a cathode, a second resistor, a second capacitor connected in series circuit arrangement with said rectifier and said second resistor, said series circuit arrangement being connected between said main cathode and said common anode, means for coupling the cathode of said rectifier to said auxiliary cathodes, means for applying a negative pulse to said control electrodes and capacitive means for deriving an output pulse from the junction point of said second resistor and the anode of said rectifier.

8. A circuit arrangement for counting pulses including a glow discharge counting tube of the type having a number of electrode groups and a common anode, each group of electrodes comprising a main cathode, an auxiliary cathode and a control electrode, the control electrodes of said groups being connected together, the auxiliary cathodes of said groups being connected together, and the discharge in said tube being transferred from one of said groups to the next of said groups by means of a negative pulse applied to said control electrodes, comprising means for connecting selected ones of said main cathodes together, a first resistor, a first capacitor connected in shunt across said first resistor, means for connecting the others of said main cathodes together and to a point at ground potential through said first resistor, the main cathode of the last of said groups being independent of the other main cathodes, means for feeding a portion of the discharge current to the auxiliary cathode of a group of electrodes and a relatively smaller portion to the main cathode of said group of electrodes, a second resistor, a second capacitor connected in shunt across said second resistor, means for connecting the main cathode of said last group of electrodes to a point at ground potential through said second resistor, a rectifier having an anode and a cathode, a third resistor, a third capacitor connected in series circuit arrangement with said rectifier and said third resistor, said series circuit arrangement being connected between said main cathode and said common anode, means for biasing said common anode at a positive potential with respect to said point at ground potential, means for applying a potential between the junction point of said rectifier and said third capacitor and said auxiliary cathodes, said last-mentioned potential being positive with respect to said point at ground potential and of relatively smaller magnitude than that of said biasing means, means for applying a negative pulse to said control electrodes and capacitive means for deriving an output pulse from the junction point of said second resistor and the anode of said rectifier.

No references cited. 

